Incidence of Dementia Decreased in Framingham Heart Study

Researchers found a decrease in dementia incidence over 3 decades for participants under surveillance since 1975.

HealthDay News — The incidence of dementia decreased over 3 decades among participants in the Framingham Heart Study, according to research published in the New England Journal of Medicine.

Claudia L. Satizabal, PhD, from the Boston University School of Medicine and colleagues described temporal trends in the incidence of dementia among participants in the Framingham Heart Study. Data were included for 5205 individuals aged 60 years or older who had been under surveillance since 1975. During each of 4 epochs, models adjusted for age and sex were used to determine the 5-year incidence of dementia.

The researchers found that the 5-year age- and sex-adjusted cumulative hazard ratios were 3.6, 2.8, 2.2, and 2.0 per 100 persons during the first (late 1970s to early 1980s), second (late 1980s to early 1990s), third (late 1990s to early 2000s), and fourth (late 2000s and early 2010s) epochs, respectively. The incidence declined by 22, 38, and 44 percent during the second, third, and fourth epochs, respectively, compared with the first epoch. The risk reduction was only seen among those with at least a high school diploma (hazard ratio, 0.77).

"Among participants in the Framingham Heart Study, the incidence of dementia has declined over the course of 3 decades," the authors wrote. "The factors contributing to this decline have not been completely identified."